I’ve been try­ing to shoot fish in an aquar­ium, with my lens up against the side of the tank. Why are most of my images blurred? Kevin Hat­field, via email

Ja­son says... There are sev­eral pos­si­ble causes. First, it could be a fo­cus­ing is­sue. Se­lect a sin­gle AF point and align it with the part of the fish you want to be in fo­cus. Use con­tin­u­ous aut­o­fo­cus to track any move­ment, and fire off a short burst in con­tin­u­ous shoot­ing mode.

Avoid slow shut­ter speeds as they can re­sult in mo­tion blur (up your ISO set­ting if nec­es­sary). Aim for a speed of 1/125 sec or faster.

Rest­ing a lens against the side of the tank can in­crease the ef­fect of mir­ror-bounce, giv­ing rise to blurred images. Ease back a lit­tle, but watch out for re­flec­tions.

You’ll need a wide aper­ture to en­able a faster shut­ter speed, so the whole of the fish may not be in fo­cus